Outline

Objective: We analyzed the outcome after radiosurgery of benign spinal tumors according to radiological findings, local control, clinical symptoms and toxicity.

Methods: A series of 36 patients with benign spinal tumors was followed prospectively. Medical history, histology and clinical symptoms were recorded. Local tumor control, clinical symptoms and adverse events have been evaluated. All patients were treated in an outpatient setting with a single irradiation fraction utilizing the CyberKnifeÂ® system (Accuray Inc. Sunnyvale CA).

Results: From 2005 until 2009 36 patients with 39 spinal lesions were treated. Median age was 45 years (C.I. 40–54), 22 female, 14 male patients. Median target volume: 3.4 ccm (C.I. 0.2–43.4). Histological diagnoses encountered 25 schwannomas and 11 meningiomas (WHO grade I). One patient suffered from neurofibromatosis type I, and two from type II. All spinal levels were affected. 17 lesions were located intraspinally, 9 also intradurally. 21 lesions were located paraspinally or intraforaminally. Median prescription dose was 14 Gy (C.I. 13.4–14) to the 70% isodose. After a median follow-up of 17 months (min 6–max 50) no local tumor progression was detected. One patient with schwannomatosis required two additional treatments of three new tumors. 42% of the lesions showed positive response without significant tumor shrinkage, in 36% slight tumor shrinkage was observed, 17% showed significant tumor shrinkage. Two patients developed an intermittent swelling of the lesion, but no progressive enlargement. Pain was the initial symptom in 13 of 21 schwannoma patients, and in 3 of 11 patients with meningiomas. A decreased pain level could be achieved in 8 patients. All but one patient with motor deficits remained stable. One patient’s sensory deficit improved. We did not see any new myelopathic signs radiographically or clinically. No irradiation side effects apart from mild nausea occurred. No higher grade toxic adverse events have been noticed.

Conclusions: Single session radiosurgery for benign spinal tumors has proven to inhibit tumor progression within the observed period without signs of early toxicity in selected patients. Radiosurgery offers an additional tool for patients not suitable for microsurgery as well as for multiple lesions, remnant or recurrent tumors.